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Forum Index : Solar : Off grid and mains powered smoke alarms
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Spoke to the building certifier today and they tell me the new regulations rule I have in install a mains powered smoke alarm in my relocated house. The battery type are not acceptable in a new building, and a relocated house is classified as a new building. The problem is a mains powered smoke alarm will want to draw a trickle of power 24 hours a day. I was hoping to have no "standy by" like devices in the house, so my inverter could shut down after I go to bed or go out for the day. So I'm not sure what to do with this smoke alarm requirement. I may have to give up on the idea of inverter shut down. Any one else come across this problem? The other option is running two mains circuits. I have a 7kW 48v inverter to run the house and workshop, but I was planning to run a 2nd system, with a little 300 watt 12v inverter, as a standby. I need the 12v for the water heater pump anyway, and the 300 watt inverter is a nice little BP pure sinewave unit. I could use it to run the smoke alarm, my clock radio and a couple of lights, like a bedroom and toilet light. That way the big inverter isn't needed during the night after I go to bed. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| Disco Stu Newbie  Joined: 13/12/2009 Location: Posts: 16 |
mite pay to double check that one, i think there may be an option for long life smoke alarms with special batterys stu |
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| windlight Guru  Joined: 03/03/2007 Location: AustraliaPosts: 331 |
Can you set your inverters trigger point low enough that the smoke alarm does not cause it to cut in? "I like this place and willingly could waste my time in it" - (Act II, Scene IV). |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Yeah I might ask the question. Maybe there is a loophole for off grid systems. I can adjust the inverters trigger point down to nothing, but running with no load it draws 0.49 amps, and in standby it draws 60mA, almost 1/10 the power. So I would rather it was in standby while I'm asleep. Half an amp isn't much, but it adds up. 0.5 amps on a 48volt system is 24 watts. For say 8 hours, thats 200Wh wasted while I sleep. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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AMACK Senior Member  Joined: 31/05/2009 Location: AustraliaPosts: 184 |
Glenn, I have a Latronic 1800watt 24 volt invertor that I use to power all the lights and some power points in the house. I to have mains wired smoke alarms that run off the lighting circuit of the house, what I do it turn up the cut in amps on the invertor so it shuts down when the Lights are off. It has a 0-30watt adjustable cut in from what I remember so it only draws 30 milliamps not 1-2 amps. Amack *Note to self 1. Make it thick 2.Make it heavy. 3.Make it stronger than it should be. 4. Don't rush the first job as the second job will cost more and take mor |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Glenn Ask for an exemption as you do not have mains power> Bob Foolin Around |
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mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412 |
Hi everyone, I have run acrost this in the electrical code as well here in the usa. We are building a Habitat for Humanity home for a family and I see that the new code requires all smoke detectors to be hard wired to the dedicated circuit, if one goes off then they all have to go off. I agree with Bob, ask for a variance in the code because you'r not on "Mains power". Mac46 I'm just a farmer |
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| windlight Guru Joined: 03/03/2007 Location: AustraliaPosts: 331 |
"mains supply" can mean "normal" source of supply, it may well be an inverter, the authors of these rules have no knowledge of living outside of a city. No single person will grant a variance, just think about it, even if they understood living away from suburbia the legalities of putting pen to paper are mind blowing. This rule in the building code came about because people forget to change the battery in their smoke detector, they see it up there and feel all warm and fuzzy but have already forgotten the battery is flat. So let's make it mandatory that it be hard wired to the "fail safe" mains supply, thanks nanny. Glenn's situation is not unique, one needs to work around the problem even though it is a burr under our saddle. Just make sure the inverter is running when the local building inspector comes to sign off on you residence, what happens after that......... Personally I started out making sure my inverter went into sleep mode over night, that was 10-12 years ago, now it's not worth the bother and that thought lasted about two weeks, if my system was so small that it was a bother I would add another panel. And just for the record I am in favor of having a working smoke detector, I fell fowl of this rule when I sold in Western Australia, I had to install one or two (depended on bedroom layout) before sale of said property in each residence, I even had to have one installed in the rest room of the fruit packing shed. Just show me the next hoop and let me out of here. Allan "I like this place and willingly could waste my time in it" - (Act II, Scene IV). |
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| neil0mac Senior Member Joined: 26/12/2009 Location: AustraliaPosts: 210 |
That should be 'thanks Granny'?? TO my mind both setups have flaws in their logic. 1. Battery powered alarms for 'flat battery syndrome'. 2. "Mains" powered alarms for 'blackout syndrome'. Ideally, buildings should have both. As far as having alarms in all 'rooms' that go off together, what happens when you have 20 rooms? Go looking for fire/smoke? The mind boggles. |
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| windlight Guru Joined: 03/03/2007 Location: AustraliaPosts: 331 |
Mains powered smoke alarms have a battery back up so are more fool proof, and how many depends on the layout of the building, if a single passage leads to all bedrooms then one at the beginning of the passage is sufficient. It is a good building code OK the writers never considered those of us living off grid but we can work around it until we are taken into account. If you will, think back to the introduction of ELCB's as mandatory on our switchboards, when they were first introduce they were a pain as items like old fridges caused them to trip, actually it may still be so that items such as fridges can be on a separate unprotected circuit. Now I would not be without one, I have a plug in one in my tool caddy. On that subject in the not too distant past there was an incident in Western Australia where a young child was electrocuted by touching an exposed wire through a hole in the Gyprock, there was no ELCB fitted to the state housing house. The ELCB was not fitted because the contractor paid to have fitted one had not( ongoing litigation), and why was there a hole in the wall cladding? I wont go there but most Australians will get my drift. Nanny is in reference to Nanny state, while I am doing my apprenticeship in bending bananas, I came from Western Australia where the governments response to every incident is to pass a law, it is out of control. Try Goggling "Jessica's law" oh hell here is a link Jessica's law. By in large existing laws cover all these knee jerk laws. And there was an incident in WA back in the 70's I think, when activists tried to stop an exploration company accessing a cattle station called Nookinbar (probably spelt wrong), anyway as a result, the WA government passed a law that any more than 3 people could not legally "meet" in a public place. All irrelevant but just to explain NANNY Allan "I like this place and willingly could waste my time in it" - (Act II, Scene IV). |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
How long does the battery backup last in the powered smoke alarms? If its like 10 or more hours, then the inverter will have kicked back in when I get out of bed. I might see if there is an exemption like Bob suggested. I agree we need smoke alarms. I'm the sort of person who likes to turn everything off ( including standby ) when I go to bed or away for a few days, so I'm pretty safe from a house fire. But, I've also been in the white goods repair business to understand how these devices can catch on fire, and thats why I believe every house should have a smoke alarm. It scares me how many people leave on something like a TV/computer monitor or cloths dryer and then go to bed or out. I've filled out several reports for these devices catching fire, one old computer monitor was left unattended for 10 minutes, the owner walked back into the room when he smelt smoke, to find the monitor and curtains behind it on fire! If he was away or asleep, the house would have burned down. Thats also why I never have curtains down behind anything electrical. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| windlight Guru Joined: 03/03/2007 Location: AustraliaPosts: 331 |
Glenn battery back up in mains powered smoke alarms last, well the same as battery powered smoke alarms, how cheep was your battery. The second part of your post I will respond to later, having recent experience with China made night lights. Allan "I like this place and willingly could waste my time in it" - (Act II, Scene IV). |
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AMUN-RA Senior Member Joined: 10/03/2007 Location: AustraliaPosts: 144 |
http://www.ata.org.au/forums/topic/3167 try this glenn looks like the problem has been solved Every day the sun shines & gravity sucks= free energy. |
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| Privatteer Newbie Joined: 09/06/2012 Location: AustraliaPosts: 39 |
Brooks smoke 12v smoke detector. Normally used in security systems but far as I am aware meets all current standards. All you need is an 12v external battery and charger. It is supposed to have a buzzer/alarm output for low battery. Alarm system normally takes care of that but it not hard to do. |
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Don B Senior Member Joined: 27/09/2008 Location: AustraliaPosts: 190 |
Hi Glenn, In the days before they had mains powered smoke alarms, the ionising chamber type battery only alarms would survive on a (fresh) battery for at least a year, sometimes two or more years. These smoke alarms really operate on the most miniscule standing draw. Note thought that I don't think that this is true for the optical ones, which I would avoid unless you are prepared for the greater current draw and hence shorter battery life. With the ionising type, as the battery voltage dropped close to inoperable levels, the smoke alarms of my experience give out a "peep" every fifteen or twenty minutes. This can go on for days or weeks. Even with the battery removed, some of them some how retain enough energy to give a final "peep". As far as I am aware, the mains powered battery backed ones still retain all of the low battery alarm features, except that the battery will not be powering the smoke detector so long as the mains is running. The battery life will therefore be equal to its shelf life (3 to 5 years???). You can test this by leaving the mains off and using an old battery, or hastening its discharge with some sort of load (resistor?) to see the effect. All this says that, with an ionising type at least, you are pretty safe to leave the mains off over night so long as you are prepared to check (and possibly replace) your detector battery annually. All I do is to check the battery voltage with a multi-meter. Anything below 9V is on the way out, so I replace it, even if it has not been peeping. I also mark the replacement date on the battery, so that I know how long it has been in service. Hope that this helps. Regards Don B |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
[quote]Note thought that I don't think that this is true for the optical ones, which I would avoid unless you are prepared for the greater current draw and hence shorter battery life. with an ionising type at least, you are pretty safe [/quote] There is very good reasons to why the style of sensor has changed, and in reality you should have both types. One will detect slow burning fires that produce cold smoke, where the older ionising ones will not but detect hotter smoke. There has been MANY programs on TV covering the types of smoke alarms and the limitations each type has, and i think many of the newer alarms use several sensor methods to solve the problems. So if you have an old smoke alarm it dont mean you are covered for all fire types. Many people have died in bed with slow burning fires that was not detected by the smoke alarm, and have suffocated with smoke in their sleep. Sometimes it just works |
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| Don B Senior Member Joined: 27/09/2008 Location: AustraliaPosts: 190 |
While I agree with Downwind that having both detector types potentially improves the chances of detecting the range of fire scenarios, the intent of my comment was to point out that the photo-optical ones require additional current to power the light source, and this will undoubtedly shorten battery life when running on batteries. In Glenn's case where the mains power would not be continuously available, at least the low battery warning (assuming that there is one in his units) would have the chance of indicating a low battery where, when the mains is continuously on, the battery could become completely inoperable as a back-up without any indication. The Wikipedia article on smoke detectors gives a fair summary of the current situation concerning smoke detection, including the point that Downwind raises. Regards Don B |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Would it be possible to build or buy a very small mini inverter, possibly only a couple of watts, just to run the smoke detectors ? Cheers, Tony. |
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| windlight Guru Joined: 03/03/2007 Location: AustraliaPosts: 331 |
Tony (Warpspeed) yes but why would one, I believe this thread started with Glenn discussing current building requirements about hard wired smoke alarms that do not take into account people living off grid (law makers can not comprehend the concept) and his inverter going into power save mode ( I could be wrong here). Smoke detectors are life savers, the simple answer is don't use a non rechargeable battery, use a 9v supply off your battery's (DC to DC converter before you ask), use a rechargeable 9v battery but piggy backed the 9v source. One thing I have learned about living off grid is DO NOT BE ANAL ABOUT YOUR POWER SUPPLY, worrying about a few watts that can be made up for with 10 minuets generator run time is counter productive, rather, enjoy the experience. Allan of the jungle "I like this place and willingly could waste my time in it" - (Act II, Scene IV). |
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| Privatteer Newbie Joined: 09/06/2012 Location: AustraliaPosts: 39 |
Easier to use something that is already compliant such as the 12v brooks detector with a 9v battery backup in it. Don B, Most if not all mains detectors beep every 15 minutes when they have no AC. Little bit annoying to have every night. |
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